1. Field of the Invention
This invention relates to improvements in O-ring sealing structures and more particularly, but not by way of limitation, to a groove for receiving the O-ring therein in a manner providing for increased sealing efficiency and prolonged life for the O-ring.
2. Description of the Prior Art
O-rings are in widespread use today for sealing between adjacent surfaces, and particularly in use in combination with the closure members of valves, such as check valve. Many of the clappers or closure members of check valves are provided with an annular groove on one face thereof for receiving an O-ring sealing member therein. A portion of the outer periphery of the O-ring normally extends beyond the outer surface of the closure member for engagement by a valve seat or the like in the closed position of the closure member. The pressure of the valve seat on the O-ring forces the O-ring into the groove and compresses the yieldable material of the O-ring into the configuration of the groove.
The usual O-ring groove is of a cross-sectional configuration similar to a dovetail groove wherein the opposite sidewalls of the groove are inwardly tapered to provide an area of compression for the O-ring and reduce accidental loss of the O-ring from the groove upon opening of the closure member. When the O-ring is compressed into the groove, considerable scrubbing occurs between the outer periphery of the O-ring and the inner periphery of the groove, and the O-rings are relatively quickly worn sufficiently to require replacement thereof. Not only is the sealing efficiency of the O-ring reduced by the scrubbing action, but the frequent replacement of the worn O-rings is time consuming and expensive.